We look at the division of 681775 by 21 
The aim is to understand the frequency of 21 in 681775.

Let's proceed to step 1:
21 goes into 6 0 times with a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Grab the next digit (8) from the dividend, add it to 6, then carry on: 68 / 21

Moving on to step 2:
When dividing 68 by 21, we get 3 with a remainder of 5.
The next digit of our result is 3. 
Result so far: 3.0
The remainder is 5 after subtracting 63 from 68.
Append the next digit (1) from the dividend to 5 and continue with: 51 / 21

Let's proceed to step 3:
21 can be fit into 51 2 times, resulting in a remainder of 9.
Use 2 as the next digit of our solution. 
Result so far: 32.0
Deduct 42 from 51 and we're left with 9.
Append the next digit (7) from the dividend to 9 and continue with: 97 / 21

Moving on to step 4:
21 goes into 97 4 times with a remainder of 13.
Use 4 as the next digit of our solution. 
Result so far: 324.0
Subtract 84 from 97 to get 13.
Append the next digit (7) from the dividend to 13 and continue with: 137 / 21

Going ahead to step 5:
137 divided by 21 is 6 with a remainder of 11.
Put 6 as the next digit of the answer. 
Result so far: 3246.0
If we take 126 away from 137, we end up with 11.
Append the next digit (5) from the dividend to 11 and continue with: 115 / 21

On to step 6:
115 divided by 21 is 5 with a remainder of 10.
Use 5 as the next digit of our solution. 
Result so far: 32465.0
Subtract 105 from 115 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Let's proceed to step 7:
When dividing 100 by 21, we get 4 with a remainder of 16.
The number 4 becomes the next digit in our result. 
Result so far: 32465.4
The remainder is 16 after subtracting 84 from 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

On to step 8:
The number 21 fits into 160 7 times, leaving a remainder of 13.
Put 7 as the next digit of the answer. 
Result so far: 32465.47
Subtracting 147 from 160 leaves us with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Moving on to step 9:
21 goes into 130 6 times with a remainder of 4.
Use 6 as the next digit of our solution. 
Result so far: 32465.476
If we take 126 away from 130, we end up with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Let's proceed to step 10:
21 can be fit into 40 1 times, resulting in a remainder of 19.
Put 1 as the next digit of the answer. 
Result so far: 32465.4761
If we take 21 away from 40, we end up with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Advancing to step 11:
190 divided by 21 is 9 with a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 32465.47619
If we take 189 away from 190, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Moving on to step 12:
21 goes into 10 0 times with a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 32465.47619
Subtract 0 from 10 to get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 13:
21 goes into 100 4 times with a remainder of 16.
Write down 4 as next digit of the result. 
Result so far: 32465.4761904
If we take 84 away from 100, we end up with 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

Advancing to step 14:
The number 21 fits into 160 7 times, leaving a remainder of 13.
Record the quotient 7 as the next digit in the result. 
Result so far: 32465.47619047
Deduct 147 from 160 and we're left with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

The quotient of the division is 32465.47619047, and the remainder is 1.3e-08.